The present invention relates to a method for making polyalkoxyaminosilanes based on the reaction between a polyalkoxysilane having a hydrogen atom attached to silicon and an amine in the presence of a transition metal catalyst.
As shown in copending application Ser. No. 277,524 of Mary Ann White et al, alkoxy silanes having leaving groups such as amino, enoxy, amido, ureido, etc., can be used as scavengers for hydroxy radicals and room temperature vulcanizable organopolysiloxane compositions to impart improved stability over extended shelf periods at ambient temperatures or under accelerated aging conditions at elevated temperatures.
Prior to the present invention N-silylamines were prepared from chlorosilanes in the presence of an excess of an appropriate amine, as shown by R. Fessenden and J. S. Fessenden, Chem. Rev. 61 361 (1961). Alkali metal amides as shown by U. Wannagat, Advanced Inorganic Radio Chemistry, 6 225 (1964), shows the preparation of N-trialkylsilylamines. Alkylaryl-N-silylamines have also been prepared using a palladium or platinum catalyst as shown by W. Fink, Helv. Chim. Acta. 49 1408 (1966).
The present invention is based on my discovery that polyalkoxyaminosilanes of the formula, ##STR1## can be made by effecting reaction between a polyalkoxysilane of the formula, ##STR2## and an amine of the formula, EQU H.sub.3-b N(R.sup.2).sub.b, (3)
where R is a C.sub.(1-8) aliphatic organic radical selected from alkyl radicals, alkylether radicals, alkylester radicals, alkylketone radicals and alkylcyano or a C.sub.(7-13) aralkyl radical, R.sup.1 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, R.sup.2 is selected from hydrogen or a C.sub.(1-8) alkyl radical and a has a value of 0 or 1 and b is a whole number equal to 0 to 2 inclusive. Reaction between the polyalkoxysilane and the amine is effected in the presence of a transition metal catalyst such as palladium.